| Since the original introduction of the WMA technologies in the USA, implementation of these procedures has progressed rapidly, but in Oklahoma, the implementation of WMA has not progressed as rapidly as anticipated. The objectives of this study were to compare laboratory and plant produced foamed WMA to conventional HMA and to develop test protocols for implementing foamed WMA into the Oklahoma DOT's mix design and quality control/quality assurance program. An ODOT S-4 and S-5 mix were selected for evaluation. Laboratory foamed mix samples were oven aged at 2, 4 and 16 hours are compared to control samples. Plant produced foamed WMA mix was sampled and tested to determine the effect of reheating on mix properties. Mix properties evaluated were Maximum Specific Gravity (AASHTO T 209), Laboratory Molded Voids (AASHTO T 166), Moisture Sensitivity (AASHTO T 283) and Hamburg Rut Testing (OHD L-55). Analysis of variance techniques were used to determine the effect of sample conditioning on mix properties. Recommendations on mix handling procedures for laboratory and plant produced foamed WMA mixtures were made. |
